Assay Method Information

Assay Name:  Binding Inhibition Assay (0.1% BSA)
Description:  The coding sequence of human DP2 was introduced into the human Leukemic cell line K562 by electroporation and stable clones expressing DP2 were obtained by limiting dilution followed by cell surface staining with a rat monoclonal antibody specific for human DP2. Membranes were prepared from one of these DP2 expressing clones and used to determine the ability of compounds of the present invention to inhibit binding of prostaglandin D2 (PGD2) to its receptor DP2 in the presence of one or more of the following serum protein concentrations, 0.1% BSA, by the following procedure. Membranes (1.25 μg/well for ).1% BSA) were mixed with 3H-labeled PGD2 and various concentrations of test compounds in 150 μL of binding buffer (50 mM Tris-HCl, pH 7.4, 40 mM MgCl2, 0.1% bovine serum albumin, 0.1% NaN3) in 96-well U-bottom polypropylene plates. After incubation for 60 minutes at room temperature, the assay was transferred to a filtration plate (#MAFB; Millipore Corporation, Bedford, Mass.), and washed three times with binding buffer. Radioactivity was measured by a scintillation counter (TopCount; PerkinElmer Life Sciences, Boston, Mass.). Nonspecific binding was determined by incubations in the presence of 1 μM unlabeled PGD2 or 5 μM of a known DP2 antagonist. EC50 values for inhibition of binding were determined for each compound tested from the inflexion point of a standard 4-parameter logistical curve fitted to the values obtained. Compounds of the invention had EC50 values less than 5 micromolar in one or more of the binding assays.
Affinity data for this assay
 

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